1. Field of the Invention
The invention relates to a field emission display and a device for driving the field emission display.
2. Description of the Related Art
A field emission display is a display device that forms images using cold cathode electrons as an electron emission source. The quality of the field emission display depends on characteristics of the electron emission source, such as the material and the structure of the electron emission source.
In general, a field emission display has a triode structure with a cathode electrode, an anode, and gate electrode. The field emission display is constructed such that the cathode electrode is formed on a substrate on which the electron emission source is placed and an insulating layer and the gate electrode are formed on the cathode electrode. The insulating layer has a contact hold and the electron emission source is formed in the contact hole whereby the electron emission source is coupled with the cathode electrode.
In a field emission display with such a structure, when electrons emitted from the electron emission source from an electron beam and go toward a corresponding phosphor, accurate focusing of the electron beam may not be achieved.
For accurate focusing, a structure has been proposed in which a mesh-type or grid-type electrode (referred to as grid electrode hereinafter) is located between the cathode electrode and the anode electrode. Voltage is applied to the grid electrode to allow the electrons emitted from the electron emission source to go toward a corresponding phosphor.
However, if the grid electrode is not provided with a proper voltage, the gate voltage influences the grid electrode to generate divergence. As such, the electrons emitted from the electron emission source reach not only the phosphor, but also other parts of the display.
Accordingly, all the electrons emitted from the electron emission source do not flow into the anode electrode, but some go into the grid electrode while the field emission display is operating. Electron emission to the grid electrode induces undesired electron flow, which may generate a surge current in the event of arcing, turning on the field emission display or timing off the field emission display, and thereby damage the device for driving the field emission display.